UNIVERSITI TEKNIKAL MALAYSIA MELAKA
DESIGN ANALYSIS OF A BABY STROLLER BY USING
DESIGN FOR MANUFACTURING AND ASSEMBLY METHOD
(BOOTHROYD DEWHURST)
This report submitted in accordance with requirement of the Universiti Teknikal
Malaysia Melaka (UTeM) for the Bachelor's Degree in Manufacturing Engineering
Technology (Product Design) (Hons.)
by
AZIE NOOR MARLIA BINTI RUSLAN
B071210430
931218-01-6116
FACULTY OF ENGINEERING TECHNOLOGY 2015
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA
TAJUK: Design Analysis of a Baby Stroller by Using Design for Manufacturing
and Assembly Method (Boothroyd Dewhurst)
SESI PENGAJIAN: 2014/15 Semester 2
Saya AZIE NOOR MARLIA BINTI RUSLAN
Mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti
Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:
1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan
untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan
pertukaran antara institusi pengajian tinggi.
4. **Sila tandakan ( )
(Mengandungi maklumat TERHAD yang telah ditentukan
oleh organisasi/badan di mana penyelidikan dijalankan) SULIT
(Mengandungi maklumat yang berdarjah keselamatan
atau kepentingan Malaysia sebagaimana yang termaktub
dalam AKTA RAHSIA RASMI 1972)
TIDAK TERHAD
TERHAD
Disahkan oleh:
______________________
AlamatTetap:
No.18, Jalan Makmur 50,
Taman Damai Jaya,
Johor Bharu.
Tarikh: ________________________
_________________________
Cop Rasmi:
Tarikh: _______________________
** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi
berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai
SULIT atau TERHAD.
DECLARATION
I hereby, declare that this report entitled “Design Analysis of A Baby Stroller by Using
Design for Manufacturing and Assembly Method (Boothroyd Dewhurst)” is the result of
my own research except as cited in the references.
Signature : ………………………………………….....
Name : AZIE NOOR MARLIA BINTI RUSLAN
Date : …………………………………………....
APPROVAL
This report is submitted to the Faculty of Engineering Technology of UTeM as a partial
fulfillment of the requirements for the degree of Bachelor of Engineering Technology
Product Design (Hons.). The member of the supervisory is as follow:
…………………………….
(Project Supervisor)
i
ABSTRAK
Projek ini menggunakan kaedah rekabentuk untuk proses dan pemasangan supaya
dapat mengkaji rekabentuk kereta sorong bayi (Sweet Cherry SCR 8 Series) dalam aspek
pembuatan, proses pemasangan dan juga kepayahan ketika memegang dan memasang
komponen. Masalah yang dikenal pasti dalam kajian ini adalah pada bentuk kereta sorong
bayi yang banyak menggunakan screw pengikat dan juga penggunaan kedua-dua belah
tangan untuk menggerakkan penyelak bagi melipat kereta sorong bayi tersebut. Objektif
projek ini adalah untuk mengurangkan komponen disamping mengekalkan fungsi kereta
sorong tersebut, untuk membuat perbezaan kadar kecekapan oleh rekabentuk asal
berbanding dengan rekabentuk baru, dan juga untuk mengurangkan jumlah waktu
pemasangan setelah analisis rekabentuk dan pemasangan dijalankan. Melalui kajian yang
telah dijalankan, terbukti dengan menggunakan kaedah ini , kos pemasangan dapat
dikurangkan sebanyak 452.29s, iaitu 23% lebih baik daripada yang sebelumnya. Kos
untuk satu bahgian juga dapat dikurangkan sebanyak RM 33.41. Bilangan bahagian juga
dapat dikurangkan daripada 179 bilangan kepada 149 bilangan sahaja. Indeks DFA juga
meningkat daripada 9.6 kepada 12.6. Kelebihan penggunaan kaedah ini telah dibuktikan
melaui rekabentuk baru untuk kereta sorong bayi
ii
ABSTRACT
This project implemented the design for manufacturing and assembly (DFMA)
methodology in order to study the design analysis of a baby stroller (Sweet Cherry SCR8
Series) in aspect of part for manufacturing, assembly process and also handling and
insertion difficulties. The problem identified in this study is on the features of the stroller
that shows a lot of fastener being used and also the usage of both hands in moving the fold
latch to fold the stroller. The objectives of this project are to reduce part while maintaining
the function of the baby stroller, to compare the efficiency of the original design and after
redesign, and also to reduce total assembly time with a new product design of a baby
stroller after DFMA analysis. The study has proven to save assembly time by 452.29s
which is 23% more efficient than the original design. Further ado, the total cost per product
for manufacturing has saved RM 33.41. The number of parts reduced from 179 parts to be
149 parts. The DFA index is also improved from 9.6 to 12.6. The advantages of using
DFMA method has been proved in the redesign of the baby stroller.
iii
DEDICATION
To my beloved parents and my brothers.
iv
ACKNOWLEDGEMENT
First and foremost I offer my sincerest gratitude to my adorable supervisor, Madam
Nurul Ain Binti Maidin, who has supported me throughout my project study with her
patience and knowledge sharing. I attribute the level of my degree to her encouragement
and effort and without this thesis, too, would not have been completed or written. One
simply could not wish for a friendlier supervisor.
In my daily life I have been blessed with my beloved parent, Mr Ruslan Bin Mohd
Dom and Mrs Kintan Binti Abdul Rahman. I owe them a deep sense of gratitude but not to
forget with my handsome big brothers, Mr Ahmad Mohammad Bin Ruslan and also Mr
Ahmad Muazzam Bin Ruslan that keep pushing me to success whenever I felt that I am not
the best.
I thank profusely both of my roommates, Ms Khalilah Binti Khalid and also Ms
Nurul Aima BintiMazlan for their kindness and co-operation throughout my study period.
v
TABLE OF CONTENTS
Abstrak i
Abstract ii
Dedication iii
Acknowledgement iv
Table of Content v
List of Tables ix
List of Figures x
List Abbreviations, Symbols and Nomenclatures xiii
CHAPTER 1: INTRODUCTION 1
1.1 Background 1
1.2 Problem Statement 2
1.3 Objectives 3
1.4 Scope of Project 3
CHAPTER 2: LITERATURE REVIEW 4
2.1 Design for Manufacturing and Assembly (DFMA) 4
2.2 Design for Assembly (DFA) 7
2.2.1 DFA Methods 7
vi
2.2.2 DFA Guidelines 10
2.2.3 DFA Product Simplication Software (BDI) 13
2.3 Design for Manufacturing 14
2.3.1 DFM Guidlines 14
2.3.2 DFM Concurrent Costing Software 15
2.4 DFMA Methodologies 15
2.4.1 Boothroyd-Dewhurst Method 16
2.5 History of A Baby Stroller 16
2.5.1 Types of Stroller 20
2.5.2 Sweet Cherry SCR8 Series 23
CHAPTER 3: METHODOLOGY 25
3.1 Introduction 25
3.2 Flowchart 26
3.2.1 Formulation of Project 27
3.2.2 Research for Literature Review 27
3.2.3 Part Identification of Baby Stroller 27
3.2.4 Run The Analysis by Using Boothroyd-Dewhurst DFMA Sotware 28
3.2.5 Redesign of The Baby Stroller 30
3.2.6 Generate Project Report 30
CHAPTER 4: RESULT & DISCUSSION 31
vii
4.1 Baby Stroller Information 31
4.2 Bill of Materials 32
4.3 Original Design for Sweet Cherry SCR8 Series 36
4.3.1 Exploded View of The Original Design 37
4.3.2 Structure Chart of The Assembly Sequences 37
4.3.3 Design for Analysis (DFA) of The Original Design 39
4.3.4 DFM Analysis of original Design 44
4.3.5 Suggestion for Redesign of Baby Stroller 47
4.4 Redesign 48
4.4.1 Exploded View of Redesign 49
4.4.2 Bill of materials 50
4.4.3 Structure Chart of Redesign 54
4.4.4 DFA Analysis of Redesign 55
4.4.5 DFM Analysis of Redesign 58
4.5 DFMA Analysis and Discussion 60
4.5.1 Design Comparison 62
4.5.2 Research Limitation 64
CHAPTER 5: CONCLUSION & RECOMMENDATION 65
5.1 Conclusion 65
5.2 Recommendation of Future Work 66
viii
REFERENCES 67
APPENDICES 69
ix
LIST OF TABLES
Table 2.1 Type of stroller nowadays
Table 4.1 Bill of materials (BOM) for original design
Table 4.2 DFA analysis of front bar part and handle part
Table 4.3 DFA analysis result for original design of Sweet Cherry SCR 8 Series
Stroller.
Table 4.4 DFM concurrent costing for front bar B of the original design
Table 4.5 Suggestion for redesign parts
Table 4.6 Bill of material for redesign
Table 4.7 DFA analysis for redesign (front bar and handle) of the baby stroller.
Table 4.8 DFA analysis result for redesign of Sweet Cherry SCR 8 stroller
Table 4.9 DFM concurrent costing for front bar of redesign for baby stroller
Table 5.1 Percent reduction for DFA analysis
x
LIST OF FIGURES
Figure 2.1 Time to deliver comparison between DFMA and CAE with Traditional
Methods
Figure 2.2 Typical steps taken in a DFMA study using DFMA software
Figure 2.3 Manual Handling and Manual Insertion –Estimated Times
Figure 2.4 Relative Cost Of Different Assembly Method By Type And Production
Volume
Figure 2.5 Production ranges for each type of assembly method
Figure 2.6 Standardize part
Figure 2.7 Geometry feature of tangle an untangled
Figure 2.8 Symmetrical part for ease of insertion
Figure 2.9 Provision of air- relief passages to improve insertion into blind holes Figure
2.10 Features affecting part handling
Figure 2.11 Provision of chamfer to allow easy of insertion
Figure 2.12 Horse-Drawn Baby Carriages (1700s)
Figure 2.13 Handles and Forward-Facing Carriages
Figure 2.14 The Pram
Figure 2.15 The Reversible Baby Carriage
Figure 2.16 The Umbrella Stroller
Figure 2.17 The Jogging Stroller
Figure 2.18 Modern stroller
Figure 2.19 Sweet Cherry SCR 8 Series Stroller
Figure 3.1 DFA Procedure.
xi
Figure 3.2 The Parameter in DFM.
Figure 4.1 The original design of Sweet Cherry SCR 8 Series Stroller
Figure 4.2 Exploded view of the original design for Sweet Cherry SCR 8 Series
Stroller.
Figure 4.3 The structure chart of the original design of the Sweet Cherry SCR 8
Series.
Figure 4.4 The evaluation properties interface in DFA analysis.
Figure 4.5 The breakdown of time per product for original design of the Sweet
Cherry SCR8 stroller (DFA)
Figure 4.6 Breakdown cost for front bar of the Sweet Cherry SCR8 stroller.
Figure 4.7 Distribution bar chart for the total cost
Figure 4.8 Redesign of Sweet Cherry SCR8 stroller
Figure 4.9 (a) Exploded view of front bar sub-assembly and bill of materials
Figure 4.9 (b) Exploded view of handle sub-assembly and bill of material.
Figure 4.10 Structure chart of redesign.
Figure 4.11 Breakdown of time per product for redesign
Figure 4.12 Breakdown of the cost for redesign of the baby stroller
Figure 4.13 Comparison of DFMA for original and redesign of the baby stroller
Figure 4.14 The comparison for breakdown of cost per product for original and
Redesign.
Figure 4.15 Design comparison of front bar
Figure 4.16 Design comparison of handle
xii
LIST OF ABBREVIATIONS, SYMBOLS AND
NOMENCLATURE
DFMA = Design for Manufacturing and Assembly
DFA = Design for Assembly
DFM = Design for Manufacturing
CAE = Computer Aided Engineering
1
CHAPTER 1
INTRODUCTION
Nowadays hundreds of stroller models are available with different branded and quality.
This made the features of the stroller to be different and unique depends on the designer
and company intention to be focused. However, the manufacturing process is the important
things to be considered as it will affect the price of the product itself. Hence, this project
focused on analyzing the design of a baby stroller in order to reduce cost then improve the
manufacturing and assembly process with a new design of a baby stroller after the analysis.
This chapter basically explain on how the project being made starting from the background
study, problem statement, objective, scope, organization of the project, and lastly result
expectations.
1.1 Background
Design for Manufacturer and Assembly in which being known as DFMA generally
is a combination of Design for Assembly (DFA) and Design for Manufacturing (DFM).
Through history of DFMA, it had been used before the Second World War by Ford and
Chrysler that using DFM philosophy in their design and manufacturing process of the
weapons, tanks and other military products. Early 1970’s the researching job of this new
technology had been done by Professors Peter Dewhurst and Geoffrey Boothroyd who
originated the Boothroyd Dewhurst, Inc. (BDI) in 1983. Initially on comprehensive work
studies, relating part characteristics to handling, fitting times and degrees of difficulties
etc., their work was genesis of the concept of “scoring” designs for DFA or DFM.
Currently Boothroyd Dewhurst methodology was the inspiration for many of its successors
around the world.
2
In essence, unstructured DFA and DFM guidelines and rules are transformed into a
structured form that can be applied using paper-based spreadsheet type analysis or
computer software. For DFA, a formalized step-by-step process being used to produce a
design metric that assesses the design efficiency related to its assemblability. The main
steps involved are based on general DFA concepts in which choose assembly method
(manual or automatic) analyze the design for ease of assembly and improve the design and
reanalyze.
Boothroyd Dewhurst’s, Inc. DFMA software is designed to be used at the concept
design stage. The aim is to optimize design for manufacture and assembly before
commitment to detail design and manufacture. The DFMA package contains a DFA
module and DFM module.
Normally the DFA module is used first, working from a concept drawing. The aim
is to improve design efficiency by eliminating of unnecessary parts, and choosing more
efficient assembly methods. This is followed by DFA, which provides estimates of time
and cost for assembly, as well as other operations. Through redesign, the design efficiency
figure is improved. This provides a relative measure between design alternative which
should influence the final design concept chosen. Meanwhile for DFM module is used to
evaluate design alternative from a manufacturing cost perspective.
This project fundamentally focused on the design analysis of Sweet Cherry SCR 8
Series Stroller by implementing DFMA method. Hence, Boothroyd Dewhurst
methodology had been used to complete this project.
1.2 Problem Statement
Nowadays, there are a lot of distinct process which all influence product cost,
quality and productivity of system that cause a huge losses to Business Company. This is
because a lot of product is made up of fasteners and redundant features (Othman, 2010).
Boothroyd Dewhurst DFA method could help to overcome the problem by suggested the
idle possible way to assemble a product with remove fastener. In a production of a baby
stroller, from the features show a lot of fastener such as screw, rivet and many more as the
structure need to be foldable. Hence, this project had analyzed the design for assembly to
3
reduce parts as well as the cost of production and come out with some improvement of the
design in an efficient way.
1.3 Objective
(a) To reduce part while maintaining the function of the baby stroller.
(b) To investigate the efficiency of the original design and after redesign (comparison)
(c) To reduce total assembly time with a new product design (redesign) of baby stroller
after DFMA analysis
1.4 Scope
In order to achieve the objective of the project, the scope had been list as shown below:
(a) Study of design for assembly of a baby stroller that focusing on mechanical parts
only by using Boothroyd Dewhurst method.
(b) Evaluate a baby stroller as a case study, analyze and redesign the product using
Boothroyd Dewhurst method.
(c) Solid Works software being used for drawing of each part and assemble of the
original and redesign of the baby stroller.
4
CHAPTER 2 LITERATURE REVIEW
As the time flies an organizations need to learn in order to improve their adaptability
and efficiency toward future. Through this idea with the help of new technologies
and philosophies of compete with other competitors literally could enhance the
development process with a good results to achieve target. Currently there are a lot of
tools that could be used to help production team to solve their problem at an early
stage. Hence, this chapter will review the past research from other sources with
citation.
2.1 Designs for Manufacturing and Assembly (DFMA)
Design for Manufacturer and Assembly (DFMA) is a tool that helps in
minimizing production cost by breaking the product down to be the simplest
components and parts. Concurrent Engineering (CE) is intended to cause developers
from the outset, to consider schedule, quality, cost, user demand and all elements of
product cycle from conception to disposal. Both of this Production Oriented Design
(DFMA and CE) could run activities simultaneously in a parallel form as being
showed in Figure 2.1 below. They were using simulation techniques that could give a
fully understanding among team member to find errors along the process and fix it
before the development ends.
5
(Sources: Junior, O.C. at. all, 2009. The White Goods Part Designed Based on DFM/DFA Concepts
in a Concurrent Engineering Environment)
Figure 2.1: Time to deliver comparison between DFMA and CAE with Traditional
Methods
There are two major concept in DFMA process in which design for assembly
(DFA) and also design for manufacturing (DFM). DFA is the design of the product
for ease of assembly (Boothroyd, 1994). It is an analysis method that brings together
multidisciplinary teams to evaluate and validate product design with respect to the
manufacture and assembly of its components parts. Meanwhile DFM is to design that
is based on reducing the cost of production and time to market for a product, while
maintaining appropriate level of quality the material and tooling side of the new
product. Hence, DFMA refers to working on both concepts together. Figure 2.2below
shows the typical steps taken in DFMA study using DFMA software.
6
(Sources: Boothroyd,G., Dewhurst,P., and Knight, W., 2002. Product Design for Manufacturing and
Assembly, 2nd
Edition, Marcel Dekker Inc)
Figure 2.2: Typical steps taken in a DFMA study using DFMA software
DFMA can be used effectively to reduce part count in the assembly that
brings to simplify the assembly process, lower manufacturing overhead cost,
minimize assembly time, and improve quality by reducing the possibilities for
introducing a defect. Also the amount of labor can be reduced once the component of
parts becomes fewer and simpler assembly processes. When the part count had been
reduced, automatically the development cycle become shortened as the philosophy
encourages simplifying the design and using standardize component whenever
possible.
7
2.2 Designs for Assembly (DFA)
Generally, there are two objective of DFA in which to minimize part count and to
have remaining parts of a nature that they are easily assembled together. The DFA
method accomplishes the objective by:
(a) Providing a tool for the designer and even design team which assures that
considerations of product complexity and assembly take place at the earliest
design stage. This eliminates the danger of focusing too much the whole
things during early design on product function with insufficient regard for
product cost and competitiveness.
(b) Guiding the designer to simplify the product so that the cost of assembly and
parts can be saving equally.
(c) Gathering information normally possessed by the experienced design
engineer and arranging it conveniently for use by less-experienced designers.
(d) Forming a database that comprises of assembly times and cost factors for
numerous design situations and production conditions.
2.2.1 DFA Methods
The analysis of a product design for ease of assembly depends to a large extent on
whether the product is to be assembled manually, fixed or hard automation, soft
automation (robotic), or a combination of these.
(a) Manual assembly
List of parts are assigned to workbenches where the component of product
being assemble manually by workers with the aids of hand tools. Even though
this is an idle method for assembly, there is usually an upper limit to the
production volume, and labor costs remain higher.
8
(Sources: Boothroyd,G., Dewhurst, P., and Knight, W.,2002. Product Design for Manufacturing and
Assembly, 2nd
Edition, Marcel Dekker Inc)
Figure 2.3: Manual Handling and Manual Insertion –Estimated Times
Top Related